Gas turbine engines contain a large variety of hollow structures. The temperatures and stresses under which most gas turbine engine components operate necessitates the fabrication of such structures from high strength, high temperature material, such as superalloys and titanium alloys. The use temperatures and stresses also require that the materials be processed by hot working rather than by casting. These materials are exceedingly difficult to and costly to machine and consequently forging processes which can produce useful, near net, shapes are highly desired.
U. S. Pat. No. 3,519,503 describes a forging process applicable to superalloys and titanium alloys, but does not disclose specific forging geometries to achieve specialized shapes. The contents of this U.S. Patent are incorporated herein by reference. Related U.S. Pat. Nos. 3,698,219, 4,265,105 and 4,312,211 are also incorporated herein by reference.
There are many hollow, symmetrically radial turbine engine components such as shafts which cannot now be forged efficiently.
Accordingly, it is an object of the invention to describe a forging process for producing hollow articles such as shafts from superalloys and titanium alloys. It is another object of the invention to describe a process for producing such hollow articles using a specific press and die arrangement without the necessity to remove the workpiece from the press between steps.